The '71-72 Milwaukee Bucks are the first of only three teams prior to 1991 to make this list. Their win total of 63 isn't as impressive as those ranked behind them, for sure -- however, their SRS of 10.7 designates them as a cut above the 2015 Warriors and Spurs. Their margin of victory of 11.16 points per game also follows suit in supporting that notion.

Larry Costello's team, in an era of high-paced teams today's NBA has never seen, managed to compete at the highest level both offensively and defensively, grading at the very top of the league in defensive rating (92.6) and second to only one in terms of offensive rating (102.6). They achieved this feat with the combined efforts of two of the best players in NBA history -- Kareem Abdul-Jabbar and Oscar Robertson.

That year, Robertson put up 17.4 points, 7.7 assists and 5.0 rebounds in 37.3 minutes per game. And if you thought The Big O was the notorious statsheet-stuffer, Abdul-Jabbar was on a whole other level, with out-of-this-world averages of 34.8 points (57.4% shooting), 16.6 rebounds and 4.6 assists across an astonishing 44.2 minutes an outing.

With that historic duo leading them, it's somewhat surprising that Milwaukee failed to make it further than Western Conference Finals, where they lost to the Lakers in six games. They were one of the greatest regular season teams of the old guard.